EU Project BRAIN

Handover in the IP-based Radio Access Network

Arndt Kadelka

Aachen University of Technology, ComNets, Germany

- Mobility Concept investigated in European BRAIN Project- Serving Global and Local IP Mobility- Performance of HiperLAN/2 Handover Procedures- Integration of HiperLAN/2 Mobility and Local IP Mobility

BRAIN System Concept using HiperLAN/2-based Access

BRAIN Radio Cells

BRAIN Radio Cells

HorizontalHandover

RNC

UTRANNode B

Node B

Roaming

VerticalHandover

SGSN

Other Networks

IP Backbone IP WAN

Supports:

- QoS for realtime services- Multicast- Handover

Serving Local and Global Mobility

Hierarchical Mobility Mobility across Wireless Access Networks served by rather slow Mobile IP Mobility within Wireless Access Network served by fast protocols, e.g., Cellular

IP, HAWAII

Local Handover within Access Network – Cellular IP

Route update by Uplink IP packets sent hop-by-hop to Gateway Router

Titel:CellIPHandover.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.

HiperLAN/2-based Radio Access Operates in the license

exempt spectrum in5-6 GHz band

Radio cells up to 200 m 25 Mbit/s typical data rate

Radio access can be adapted to various networksBRAIN: IP Conv. Layer

Actions to Perform a handover

In H/2 fast handover decision and execution is performed by the MTs:

1. Scanning for alternative channel, i.e., served by different APT• MT indicates absence to serving AP, AP stops data transmission

• MT performs measurements on alternative channel(s)

• MT may return to serving AP or perform a handover

2. Handover decision• MT decides to perform a handover based on RSSI and PER measurements

• Hysteresis to avoid ping-pong-effects

3. Handover execution• MT may indicate handover intention to serving AP

• MT initiates handover by Handover_Request to target APT, i.e, forward handover

• Re-establishment of link layer communication

Scanning Period

Packet Transmission Delay owing to Scanning

Downlink Transmission Uplink Transmission

Amount of data effected by scanning:absentpresent

absent

tt

t

Handover within H/2 Radio Access Network

Radio HO performed within DLC IP layer not involved

Inter-Subnet Network Handover involves also IP layer Route update of IP routing tables

Titel:HL_2_Subnetze_quer.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.

Radio Handover Execution

Titel:NormalAndRadio_fertig2.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.

Serving Local Mobility with H/2

Changing point of attachment to the network

Re-establishment of link layer communication via the air interface

Re-registration to the IP network Authentication Maintaining on-going DLC connections

Integration with IP mobility via IP CL

Slow Network Handover Procedure

Interworking with Cellular IP IP CL triggers route update packet

Loss of IP packets received at APold before route update execution

Titel:WorstCase_NW_HO_procd.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.

Analysis of Slow Network Handover

Packet Loss during Slow Network Handover

Fast Network Handover with Backbone Signaling

Information about on-going DLC connections retrieved via backbone

Packets routed to APold are tunneled to APnew

DLC address of APold is indicated during HO_Association

AP has to maintain address mapping table APold DLC IP address

Fast Network Handover ProcedureTitel:BestCase_NW_HO_procd.epsErstellt von:fig2dev Version 3.2 Patchlevel 3cVorschau:Diese EPS-Grafik wurde nicht gespeichertmit einer enthaltenen Vorschau.Kommentar:Diese EPS-Grafik wird an einenPostScript-Drucker gedruckt, aber nichtan andere Druckertypen.

Analysis of Fast Network Handover

Making use of Slow and Fast Network Handover To make best use of Fast Network Handover procedure IP

address of old AP must be known Mapping table may be set up

manually, by operation and maintenance procedures administration effort not flexible

dynamically, by following procedure

1. AP selects handover procedure to be executed, i.e., Slow or Fast Network Handover

2. MT performing 1st Handover from APold to Apnew carries out Slow Network Handover and provides DLC address (during HO_Association) and IP address of Apold (via Info_Transfer)

3. Stores DLC/IP-address mapping

4. Subsequent handovers from this APold are performed according Fast Handover procedure

Conclusion

H/2 defines handover procedures to serve local mobility For H/2 mobility integration with IP local mobility interworking

functions are investigated and defined for the new IP CL To perform network handover involving the IP network almost

as fast as radio handover address mapping table has to be maintained in IPCL

Procedure defined to set up the mapping table dynamically

Work will be continued in follow-up project MINDSpecification of IPCL and contribution to ETSI/BRANMobility integration with UMTS (Vertical Handover)